The hypothesis of this study is that an 18-month exercise program will positively effect body weight and body composition in moderately overweight college students. The specific aims of this study are: 1) to determine the effects of an 18-month period of supervised, verified exercise, resulting in an approximate increase in energy expenditure of 140,800 Kcal on body weight and body composition in overweight college students, 2) to determine the manner in which exercise alters energy balance through changes in energy intake and total energy expenditure, leading to the observed changes in body weight and composition, and 3) to determine if an 18-month period of exercise reduces risk factors for cardiovascular disease and diabetes. The immediate goal in the treatment of obesity is to reduce body weight and thus, reduce health risk. This may be achieved by a variety of interventions which produce a negative energy balance through energy restriction, exercise, or both.